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 ###Instrução: Qual é a média de anos das partidas de simples feminino de Maja Pohar?
 ###Tabelas: CREATE TABLE previous_winners (previous_winners_id AUTO_INCREMENT PRIMARY KEY, Year INT, Men's singles VARCHAR, Women's singles VARCHAR, Men's doubles VARCHAR, Women's doubles VARCHAR, Mixed doubles VARCHAR) CREATE TABLE peter_drummond_1911-1918 (peter_drummond_1911-1918_id AUTO_INCREMENT PRIMARY KEY, Class VARCHAR, Wheels INT, Date VARCHAR, Builder VARCHAR, No. built INT, 1919 nos. VARCHAR, LMS Class VARCHAR, LMS nos. VARCHAR) CREATE TABLE comparison_of_toy_group_breeds_of_major_kennel_clubs (comparison_of_toy_group_breeds_of_major_kennel_clubs_id AUTO_INCREMENT PRIMARY KEY, The Kennel Club (UK) Toy Group VARCHAR, Canadian Kennel Club Toy Dogs Group VARCHAR, American Kennel Club Toy Group VARCHAR, Australian National Kennel Council Toy Dogs Group VARCHAR, New Zealand Kennel Club Toy Group VARCHAR) CREATE TABLE ppl_2005__final_standings (ppl_2005__final_standings_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Played INT, Drawn INT, Lost INT, Points INT) CREATE TABLE elections_to_congress_of_deputies (elections_to_congress_of_deputies_id AUTO_INCREMENT PRIMARY KEY, Election number INT, Election date VARCHAR, District VARCHAR, Province VARCHAR, Took office VARCHAR, Left office VARCHAR)  
SELECT AVG Year FROM previous_winners WHERE Women's singles = maja pohar